How the vestibular system interacts with somatosensory perception: A sham-controlled study with galvanic vestibular stimulation

Elisa R Ferrè,Brian L Day,Gabriella Bottini,Patrick Haggard

doi:10.1016/j.neulet.2013.06.046

Elisa R Ferrè, Brian L Day + Show 2 more

Open Access

https://doi.org/10.1016/j.neulet.2013.06.046

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Abstract

The vestibular system has widespread interactions with other sensory modalities. Here we investigate whether vestibular stimulation modulates somatosensory function, by assessing the ability to detect faint tactile stimuli to the fingertips of the left and right hand with or without galvanic vestibular stimulation (GVS). We found that left anodal and right cathodal GVS, significantly enhanced sensitivity to mild shocks on either hand, without affecting response bias. There was no such effect with either right anodal and left cathodal GVS or sham stimulation. Further, the enhancement of somatosensory sensitivity following GVS does not strongly depend on the duration of GVS, or the interval between GVS and tactile stimulation. Vestibular inputs reach the somatosensory cortex, increasing the sensitivity of perceptual circuitry.

Highlights

The cortical vestibular system is strongly integrated with other sensory modalities, including somatosensory processing [14]
We investigate whether vestibular stimulation modulates somatosensory function, by assessing the ability to detect faint tactile stimuli to the fingertips of the left and right hand with or without galvanic vestibular stimulation (GVS)
We previously reported that cold caloric vestibular stimulation (CVS) increases tactile sensitivity on the fingers of both hands [4,6]

Summary

Introduction

The cortical vestibular system is strongly integrated with other sensory modalities, including somatosensory processing [14]. We previously reported that cold caloric vestibular stimulation (CVS) increases tactile sensitivity on the fingers of both hands [4,6]. Somatosensory potentials evoked by median nerve stimulation are modulated by CVS [5]. During CVS participant’s ear is irrigated with cold water for few seconds. This technique does not permit a complete control of the parameters of the stimulation, for example the exact volume of water going into the external ear canal and the precise timing of the stimulation of the vestibular organs. Non-vestibular contributions to CVS-induced modulation of somatosensory processing, for example due to the cold sensation in the outer ear, cannot be ruled out, because of the absence of reliable sham stimulation

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